Reconfigurable control architectures and algorithms for electric vehicle wireless energy transfer systems

ABSTRACT

A control architecture for electric vehicle wireless power transmission systems that may be segmented so that certain essential and/or standardized control circuits, programs, algorithms, and the like, are permanent to the system and so that other non-essential and/or augmentable control circuits, programs, algorithms, and the like, may be reconfigurable and/or customizable by a user of the system. The control architecture may be distributed to various components of the wireless power system so that a combination of local or low-level controls operating at relatively high-speed can protect critical functionality of the system while higher-level and relatively lower speed control loops can be used to control other local and system-wide functionality.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority to U.S.application Ser. No. 13/612,494 filed Sep. 12, 2012, which claims thebenefit of U.S. provisional patent application 61/532,281 filed Sep. 12,2011 and U.S. provisional patent application 61/566,450 filed Dec. 2,2011, whose disclosure contents are hereby incorporated by reference intheir entirety.

BACKGROUND

Field

This disclosure relates to wireless energy transfer and methods forcontrolling the operation and performance of electric vehicle wirelesspower transmission systems.

Description of the Related Art

Energy or power may be transferred wirelessly using a variety of knownradiative, or far-field, and non-radiative, or near-field, techniques asdetailed, for example, in commonly owned U.S. patent application Ser.No. 12/613,686 published on May 6, 2010 as US 2010/010909445 andentitled “Wireless Energy Transfer Systems,” U.S. patent applicationSer. No. 12/860,375 published on Dec. 9, 2010 as 2010/0308939 andentitled “Integrated Resonator-Shield Structures,” U.S. patentapplication Ser. No. 13/222,915 published on Mar. 15, 2012 as2012/0062345 and entitled “Low Resistance Electrical Conductor,” U.S.patent application Ser. No. 13/283,811 published on Oct. 4, 2012 as US2012/024898 and entitled “Multi-Resonator Wireless Energy Transfer forLighting,” the contents of which are incorporated by reference.

Recharging the batteries in full electric vehicles currently requires auser to plug a charging cord into the vehicle. The many disadvantages ofusing a charging cord, including the inconvenience, weight, andawkwardness of the cord, the necessity of remembering to plug-in andun-plug the vehicle, and the potential for cords to be stolen,disconnected, damaged, etc., have motivated makers of electric vehiclesto consider wireless recharging scenarios. Using a wireless powertransmission system to recharge an electric vehicle has the advantagethat no user intervention may be required to recharge the vehicle'sbatteries. Rather, a user may be able to position a vehicle near asource of wireless electricity and then an automatic control system mayrecognize that a vehicle in need of charge is present and may initiate,sustain, and control the delivery of wireless power as needed.

One of the advantages of wireless recharging of electric vehicles isthat the vehicles may be recharged using a variety of wireless powertechniques while conforming to a variety of performance criteria. Thevariety of available wireless power techniques and acceptableperformance criteria may present challenges to system designers who maylike to provide for interoperability between different wireless sourcesand wireless devices (usually integrated in the vehicles) and at thesame time differentiate their products by offering certain enhancedfeatures. Therefore there is a need for an electric vehicle wirelesspower system control architecture that may ensure safe, efficient andreliable performance that meets certain industry performance standardsand that offers designers and users of the end-system the opportunity tocustomize their systems to offer differentiated and enhanced features tothe drivers of their vehicles.

SUMMARY

This invention relates to a control architecture for electric vehicle(EV) wireless power transmission systems that may be segmented so thatcertain essential and/or standardized control circuits, programs,algorithms, and the like, are permanent to the system and so that othernon-essential and/or augmentable control circuits, programs, algorithms,and the like, may be reconfigurable and/or customizable by a user of thesystem. In addition, the control architecture may be distributed tovarious components of the wireless power system so that a combination oflocal or low-level controls operating at relatively high-speed canprotect critical functionality of the system while higher-level andrelatively lower speed control loops can be used to control other localand system-wide functionality. This combination of distributed andsegmented control may offer flexibility in the design and implementationof higher level functions for end-use applications without the risk ofdisrupting lower level power electronics control functions.

The inventors envision that the control architecture may comprise bothessential and non-essential control functions and may be distributedacross at least one wireless source and at least one wireless device.Non-essential control functions may be arranged in a hierarchy so that,for example, more sophisticated users may have access to more, ordifferent reconfigurable control functions than less sophisticatedusers. In addition, the control architecture may be scalable so thatsingle sources can interoperate with multiple devices, single devicescan interoperate with multiple sources, and so that both sources anddevices may communicate with additional processors that may or may notbe directly integrated into the wireless power charging system, and soon. The control architecture may enable the wireless power systems tointeract with larger networks such as the internet, the power grid, anda variety of other wireless and wired power systems.

An example that illustrates some of the advantages of the distributedand segmented architecture we propose is as follows. Imagine that anoriginal equipment manufacturer (OEM) of an EV wireless powertransmission system may need to provide a system with certain guaranteedand/or standardized performance such as certain end-to-end transmissionefficiency, certain tolerance to system variations, certain guaranteesfor reliability and safety and the like. An integrator who integratesthe wireless power transmission system into an electric vehicle may wishto distinguish their vehicle by guaranteeing higher efficiency and/ormore robust safety features. If the control architecture is structuredin such a way that the integrator can set certain thresholds in thecontrol loops to ensure higher efficiency and/or may add additionalhardware (peripherals) to the system to augment the existing safetyfeatures, then the integrator may be able to offer significant productdifferentiation while also guaranteeing that basic system requirementsand/or standards are met. However, if the control architecture is notsegmented to offer some reconfigurable functions while protecting thecritical functions of the wireless power system, changing certaincontrol loops and/or adding additional hardware may disrupt the requiredlow-level power delivery, reliability, and safety performance of thesystem.

Note that the inventive control architecture described in thisdisclosure may be applied to wirelessly rechargeable electric vehiclesusing traditional inductive and magnetic resonance techniques. Becausethe performance of traditional inductive wireless power transmissionsystems is limited compared to the performance of magnetic resonancepower transmission systems, the exemplary and non-limiting embodimentsdescribed in this disclosure will be for magnetic resonance systems.However, it should be understood that where reference is made to sourceand device resonators of magnetic resonance systems, those componentsmay be replaced by primary coils and secondary coils in traditionalinductive systems. It should also be understood that where an exemplaryembodiment may refer to components such as amplifiers, rectifiers, powerfactor correctors and the like, it is to be understood that those arebroad descriptions and that amplifiers may comprise additional circuitryfor performing operations other than amplification. By way of examplebut not limitation, an amplifier may comprise current and/or voltageand/or impedance sensing circuits, pulse-width modulation circuits,tuning circuits, impedance matching circuits, temperature sensingcircuits, input power and output power control circuits and the like.

In one aspect of the invention a wireless energy transfer system mayinclude a segmented control architecture. The wireless system mayinclude a primary controller and a user configurable secondarycontroller that is in communication with the primary controller. Theprimary controller may be configured to perform the essential controlfunctions for the wireless system. The essential control functions ofthe primary controller may include maintaining the wireless energytransfer operating safety limits. The primary controller may monitor andcontrol the voltage and currents on the components of the wirelessenergy transfer system. The user configurable secondary controller maybe configured to allow adjustment of non-safety critical parameters ofthe system such as adjusting the maximum power output, scheduling of onand off times, adjusting the frequency of energy transfer, and the like.In accordance with exemplary and non-limiting embodiments the primaryand secondary controllers may be implemented on separate hardware orprocessors. In other exemplary embodiments the primary and secondarycontrollers may be virtual controllers and implemented on the samehardware.

BRIEF DESCRIPTION OF FIGURES

FIG. 1 shows exemplary components in an electric vehicle wireless powertransfer system.

FIG. 2 shows an exemplary charging system control diagram for anelectric vehicle wireless power transfer system. This exemplaryembodiment shows that system performance may be monitored with a laptopthrough the wireless and/or wired “Debug” and “Status” ports.

FIG. 3 shows a notional state diagram of the system charging cycle.Activation states are denoted by the rectangles. Conditional statementsthat enable transitions between states are enclosed in square brackets.Fault detection on either side results in both sides entering theAnomaly state.

FIG. 4 shows an exemplary charging cycle use-case.

FIG. 5 shows a Sequence Diagram for interaction between a source and anelectric vehicle during an exemplary charging engagement.

FIG. 6 shows an exemplary embodiment of power factor corrector controlloops.

FIG. 7 shows an exemplary embodiment of source amplifier control loops.

FIG. 8 shows an exemplary embodiment of device rectifier control loops.

FIG. 9 shows exemplary interfaces to and from an application sourceprocessor.

FIG. 10 shows exemplary interfaces to and from an application deviceprocessor.

FIG. 11 shows exemplary interfaces to and from an amplifier controller.

FIG. 12 shows exemplary interfaces to and from a rectifier controller.

FIG. 13 shows exemplary ASP control parameters.

FIG. 14 shows exemplary ADP control parameters.

FIG. 15 shows exemplary amplifier control parameters.

FIG. 16 shows exemplary rectifier control parameters.

DETAILED DESCRIPTION

This disclosure describes exemplary reconfigurable system controlconcepts for electric vehicle wireless power transmission systems. Ingeneral, an electric vehicle (EV) may be any type of vehicle such as acar, a boat, a plane, a bus, a scooter, a bike, a cart, a movingplatform, and the like that comprises a rechargeable battery. Thewireless power transmission system may provide power to the batterycharging circuit of the electric vehicle and/or it may power the vehicledirectly. Wireless power may be provided to the vehicle while it isstationary or while it is moving. The power provided wirelessly torecharge the vehicle battery may be more than 10 Watts (W), more than100 W, more than a kilowatt (kW), more than 10 kW, and/or more than 100kW, depending on the storage capacity and power requirements of thevehicle. In some exemplary low power embodiments, fewer control loopsand/or less distributed and/or less segmented control architectures maybe sufficient to ensure safe, reliable and efficient operation of thewireless power transmission system. In some exemplary high powerembodiments, redundant control loops and/or multi-level controlarchitectures may be required to realize safe, reliable and efficientoperation of the wireless power transfer system.

This disclosure describes certain control tasks that may be necessaryfor enabling an electric vehicle charging engagement using a wirelessenergy transfer system as well as potential control loops, states, andsequences of interactions that may govern the performance of the system.The proposed control architectures and tasks may enable transactionmanagement (e.g. billing, power origination identification, direction ofpower flow), integration with vehicle electronics, and higher levelcontrol tasks for system operation, communications, and anomalyresolution. Throughout this disclosure we may refer to certainparameters, signals, and elements as being variable, tunable,controllable, and the like, and we may refer to said parameters, signalsand elements as being controlled. It should be understood that systemparameters, signals and elements may be controlled using hardwarecontrol techniques, software control techniques, and/or a combinationsof hardware and software control techniques, and that these techniquesand the circuits and circuit elements used to implement them may bereferred to as controllers and/or system controllers.

A block diagram of an exemplary wireless electric vehicle (EV) batterycharging system is shown in FIG. 1. In this embodiment the system ispartitioned into a source module 101 and a device module 102, with eachmodule consisting of a resonator 103, 104 and module control electronics105, 106. The source module 101 also consists of a power factorcorrector (PFC) 108 and an amplifier 109. The device module 102 alsoconsists of a rectifier 110. The source module 101 may be part of acharging station and the device module 102 may be mounted onto avehicle. Power may be wirelessly transferred from the source 101 to thedevice 102 via the resonators 103, 104. Closed loop control of thetransmitted power may be performed through a communications link 107between the source 101 and the device 102. The communications link 107can be an out-of-band communications link, an in-band communicationslink, or a combination of in-band and out-of-band signaling protocolsbetween the source 101 and device 102. In some embodiments, some or allof the system control functions may be realized in a computer,processor, server, network node and the like, separated from the source101 and device 102 modules. In some embodiments, the system controllermay control more than one source, more than one device and/or more thanone system.

A wireless power transmission system for electric vehicle charging canbe designed so that it may support customization and modifications ofthe control architecture. Such customizations and modifications may bereferred to as reconfigurations, and an architecture designed to supportsuch reconfigurations may be referred to as reconfigurable. In someexemplary and non-limiting embodiments, the control architecture may berealized in physically separate components, such as multiplemicroprocessors and some functions, processes, controls, and the likemay be reconfigurable by a user of the system, and some may not. In someexemplary and non-limiting embodiments, the reconfigurable portions ofthe control architecture may be implemented in certain chips,micro-processors, field programmable gate arrays (FPGAs), PeripheralInterface Controllers (PICs), Digital Signal Processors (DSPs),Application Specific Processors (ASPs), and the like. In an exemplaryembodiment, some reconfigurable portions of the control architecture mayreside in ASPs which may be 32-bit microcontrollers with C-languagesource code. In some exemplary and non-limiting embodiments, the controlcode may reside on a single processor and a user may have permission toaccess certain portions of the code. In exemplary and non-limitingembodiments, both hardware and software segmentation of the controlfunctions of an EV wireless power transmission system are contemplatedin this disclosure.

In an exemplary embodiment, the system architecture may support ASPs inthe source 101 and device 102 modules and these processors may bereferred to as Application Source Processors (ASP) and the ApplicationDevice Processors (ADP). This control architecture may enable differentusers and/or manufacturers of different vehicles and vehicle systems tobe able to add to the source code or customize it for integration withtheir vehicles and/or in their intended applications. Throughout thisdisclosure we may use the terms processor, microprocessor, controller,and the like to refer to the ASPs described above and any suitable typeof microprocessor, field programmable gate array (FPGA), PeripheralInterface Controller (PIC), Digital Signal Processor (DSP), and thelike, that is known to one of skill in the art. In embodiments, the ASPand ADP may be used to present certain system parameters and controlpoints to wireless power system designers and/or vehicle integrators andto restrict access to certain other system parameters and controlpoints. For example, certain control features may be essential to ensureproper and/or safe operation of a wireless power transmission system,and such control features may be implemented in hardware only loopsand/or in physically separated microcontrollers and/or in restrictedportions of the ASPs so that they may not be customized and/or modifiedby certain users of the systems.

In exemplary and non-limiting embodiments, one, some or all of thecontrol functions of the wireless power system may be based on hardwareimplementations and/or may be hard-coded into the system and/or may besoft-coded into the system but with restricted access so that onlyselect and verified users may make changes to the various codes,programs, algorithms and the like, that control the system operation.

Note that whether or not the functionality associated with the ASPs inthis exemplary embodiment are realized in physically separate hardwarecomponents or in isolated sections of code, the concept of partitioningthe control plane into at least source-side and device-side functionsand into at least high-level and low-level functions is what enables thereconfigurability of system operation while guaranteeing certain safety,reliability and efficiency targets are met. The distribution andsegmentation of the control plane allows flexibility in the adaptationof the higher level functions for vehicle designer and/or end userapplications without the risk of disrupting the operation of the lowlevel power electronics control functions. In addition, the partitioningof the control plane allows for variable control loop speeds; fast andmedium speeds for the low level critical hardware control functions ofthe power electronics as well as slower control loop speeds for the highlevel designer and/or end user control loops.

As time goes on, this partitioned control plan architecture may scale toadjust to and support more functionality and applications, at the sametime it may be adapted to changing hardware requirements andstandardized requirements for the safe and efficient delivery of power.For example, the fast and medium speed control loops may be adapted tosupport wireless power transmission at a range of operating frequenciesand over a range of coupling coefficients, both of which may eventuallybe set by regulatory agencies. Also, users may access and customize thehigher level control functions to implement functionality that mayinclude, but may not be limited to:

-   -   Programming an EV wireless source to connect through a wired        internet connection in the source, or through Wi-Fi or the        cellular network to display certain source attributes such as        what type of resonator it comprises, how much energy it can        supply, what the price is for the energy it supplies (this price        may change during the day, being less expensive at night when        the peak demand for electricity is lower, or it may change        seasonally, costing more when the temperature is hot and air        conditioning requirements are stressing the electrical supply),        where the energy it supplies originates from (renewables, coal        plant, etc.), does this source require a reservation, if it        requires a reservation, when are the free times that can be        reserved, what type of FOD detectors does it deploy, what is the        status of the source (has FOD been detected and needs to be        cleaned off before charging can be initiated, or has FOD been        detected and so the source can only supply a limited amount of        power).    -   Programming an EV wireless power transfer system so that it may        connect to a communication network and may contact the vehicle        user to report the status of the charge cycle and to report when        charging is complete or when charging has been interrupted or        that the source and/or device are in an anomaly state.    -   Programming an EV wireless power transfer system so that power        is transmitted from the device back to the grid and managing the        transaction so that the vehicle user is paid for supplying that        energy.    -   Programming a user interface in the vehicle so that information        regarding the position of the vehicle resonator relative to the        source resonator can be relayed to the driver of the vehicle.        The relative position information may be used to give the        vehicle driver an estimate of the wireless transfer efficiency        with the vehicle in its current location and may offer the        driver a chance to change the parking position to improve the        wireless system performance. The user interface may include        visible, audible, vibrational and the like feedback to help the        driver reposition the vehicle.

Programming an EV wireless power transfer system so that it communicateswith an automatic vehicle parking capability resident on the vehicle andparks the vehicle in a position that is optimized for wireless powertransfer efficiency. Other commands that may be communicated from the EVwireless power transmission system to the vehicle may include commandsto control the active suspension of the vehicle to raise or lower thevehicle relative to the source to optimize wireless power transfer.

FIG. 2 shows an exemplary charging system control diagram for anelectric vehicle wireless power transfer system. In this block diagram,the source components 201 of the system are shown on the left side ofthe diagram and the device (or vehicle) components 202 of the system areshown on the right. The source components 201 include a power factorcorrector 204, a switching amplifier 205, an amplifier controller 206,an ASP 208 and a source coil 207. The device components 202 include anADP 210, a rectifier controller 211, a rectifier 212 and a device coil213.

In embodiments, AC line power 203 may flow into a power factor corrector(PFC) 204 and provide a DC voltage to a switching amplifier 205. Inembodiments, the DC voltage provided to the switching amplifier 205 maybe variable and may be controlled. In exemplary and non-limitingembodiments, a DC voltage may be provided to the amplifier 205 from a DCsource of power (not shown) such as a solar cell, a battery, a fuelcell, a power supply, a super capacitor, a fly wheel, and the like. Inembodiments, the DC voltage from a DC power source may be variable andmay be controlled.

The switching amplifier 205 in the source 201 of an electric vehiclewireless power transmission system may be any class of switchingamplifier including, but not limited to, a class D amplifier, a class Eamplifier and a class D/E amplifier. The switching frequency of theamplifier 205 may be any frequency and may preferably be a frequencypreviously identified as suitable for driving inductor coils and/ormagnetic resonators. In embodiments, the switching frequency may bebetween 10 kHz and 50 MHz. In embodiments, the frequency may beapproximately 20 kHz, or approximately 44 kHz, or approximately 85 kHz,or approximately 145 kHz, or approximately 250 kHz. In embodiments, theswitching frequency may be between 400 and 600 kHz, between 1 and 3 MHz,between 6 and 7 MHz, and/or between 13 and 14 MHz. In embodiments, thefrequency of the switching amplifier 205 may be tunable and may becontrolled.

In embodiments, an amplifier controller 206 may manage the electroniccomponents in the amplifier 205 and/or in the PFC 204 and/or in the DCpower supply (not shown). The amplifier controller 206 may monitor andcontrol so-called local control loops and local interlocks forconditions such as over voltage/current in the source electronics,ground-fault circuit interrupt in the source electronics, andout-of-specification AC impedance changes at the source coil 207. Inembodiments, the amplifier controller 206 may react quickly to shut thesystem down safely in response to a variety of set point violations. Theamplifier controller 206 may expose registers for set-points and controlto the ASP through an inter-integrated circuit (I²C) interface, referredto in the figure as the “User Interface”. The amplifier controller 206may also have a watchdog timer (or heartbeat input) to detect ifcommunication with the Application Source Processor (ASP) 208 or withthe vehicle has been lost.

In an exemplary embodiment, the ASP 208 may provide high-level controlof the source electronics and the overall system charging cycle. Forexample, the ASP 208 may interface with a foreign-object-debris (FOD)detector that monitors the source module 201 for the presence of FODand/or excessive temperature. The ASP 208 may be connected to an in-bandand/or out-of-band communications link 209 that may communicate with thevehicle-side application device processor (ADP) 210 to provide closedloop control of the charging cycle.

In an exemplary embodiment on the vehicle side 202 (also called thedevice side), a rectifier controller 211 may perform low-level and localfunctions for the device side 202 that are analogous to those describedfor the source side 201. Again, an I²C interface may be provided forinterfacing with a higher-level ADP. The ADP 210 could be configured toconnect via a CAN-bus or equivalent to a battery manager that maycontrol the power delivered from the rectifier 212 to the battery,vehicle engine or any time of power storage or management system on thevehicle. The ADP 210 could communicate that information to thesource-side ASP 208 which, in turn, could adjust the power settings onthe amplifier controller 206.

In an exemplary embodiment, the control architecture may be partitionedinto three types of control loops: fast, medium and slow. The fastcontrol loops may be for time critical functions (less than 1-mslatency) and may be either hardware control loops or interrupt-drivenlow-level software modules. Medium-speed control loops may be forfunctions that operate under real-time software control (<500-mslatency). Slow control loops (>500 ms latency) may be for functions withlow bandwidth requirements or functions with unpredictable latency, forexample, a 802.11-family wireless communication link.

FIG. 2 shows the three types of control loops as they may be applied toan exemplary electric vehicle wireless power transmission system. Inembodiments, embedded software portions of the control loops may bepartitioned between the amplifier and rectifier controllers 206, 211,respectively, and the processors (ASP 208 and ADP 210). The amplifierand rectifier controllers 206, 211, respectively, may handle thehardware control and the operation of high-power and/or sensitiveelectronics components. The ASPs may handle the system control loop andmay provide interfaces to external peripherals, such as FOD detectors,communication links, monitoring equipment, and other vehicle and sourceelectronics.

In exemplary and non-limiting embodiments, some of the functions thatmay operate under fast feedback-loop control may be based on hardwareset-points and/or on software (programmable) set-points which mayinclude but may not be limited to over-current protection, over-voltageprotection, over-temperature protection, voltage and current regulation,transistor shoot-through current in the switching amplifier, GFCI(ground fault circuit interrupt) and critical system interlocks. Inexemplary and non-limiting embodiments, system events that may causedamage to the system itself or to a user of the system in a short periodof time may be detected and reacted to using fast feedback-loop control.

In exemplary and non-limiting embodiments, some of the functions thatmay operate under medium-speed feedback loops may include, but may notbe limited to temperature set-point violations, impedance set points todeclare an out-of-range condition for the source coil impedance, FODdetection, monitoring for violations of the minimum efficiency setpoint, local power control in the source-side electronics and processorheartbeat monitoring (i.e. watchdog-timer expiration). In exemplary andnon-limiting embodiments, system events that may cause damage to thesystem itself or to a user of the system in a medium period of timeand/or that may cause the system to operate in an undesirable state(e.g. low efficiency) may be detected and reacted to using mediumfeedback-loop control.

In exemplary and non-limiting embodiments, some of the functions thatmay operate under relatively slow-speed loop control may include but maynot be limited to system power control loop (e.g. for executing abattery-charging profile), charge request/acknowledge messages betweenvehicle(s) and source(s), system start/stop messages, system levelinterlocks, RF communications link heartbeat monitoring (i.e.watchdog-timer expiration), status/GUI updates to a diagnostic laptopand messages for source/vehicle transactions, authentication andconfiguration. In exemplary and non-limiting embodiments, system eventsthat may cause damage to the system itself or to a user of the system ina long period of time and/or that may cause the system to operate in anundesirable state (e.g. low efficiency, insufficient information forclosing a transaction) may be detected and reacted to using slowfeedback-loop control.

FIG. 3 shows a notional state diagram of the system charging cycle. Thediagram shows examples of state machines that may be running on the ASPsin the source side 301 and the vehicle side 302 of the EV wireless powertransmission system. Potential activation states are shown within eachrectangle and potential conditional statements that must be satisfied toenable transitions between states are enclosed in square brackets. Inembodiments, in-band, out-of-band, and/or a combination of in-band andout-of-band wireless communication links between the source and thevehicle may provide for messaging and synchronization. In embodiments,the communications required to implement control functions, processesand the like may piggy-back on existing or native communication systemsin and around the vehicle. For example, messages may be passed amongstthe source(s), the vehicle(s), and any additional networked component(s)using CAN-bus equipment and protocols, Bluetooth equipment andprotocols, Zigbee equipment and protocols, 2.4 GHz radio equipment andprotocols, 802.11 equipment and protocols, and/or any proprietarysignaling scheme equipment and protocols implemented by the user.

For charging electric vehicles that may be described in the standardsproposed by the Society of Automotive Engineers (SAE), the chargingengagement between the source and vehicle for wireless charging may besimilar to that described by SAE J1772 for wired charging, withadditional steps added to support wireless charging.

An exemplary use-case for stationary EV charging involving the operationof the control system is shown in the table in FIG. 4. In an exemplaryembodiment, a wireless source may be powered and available to supplypower to a wireless device and may be referred to as being in theAvailable state. A wireless source may constantly, periodically,occasionally and/or in response to some trigger, broadcast informationregarding any of its availability, position, location, power supplycapabilities, power costs, power origination (solar, coal burning plant,renewable, fossil fuel, etc.), resonator type, resonator cross-section(so that a vehicle may calculate and/or look-up an expected couplingcoefficient with the source), and the like. A vehicle may be receivinginformation broadcast by wireless power sources and may search for anavailable wireless power source, with matching hard-wired and/or useselectable features, over which it may park. The vehicle's communicationlink may be active so that it is in the Searching state. If vehicleidentifies a suitable wireless source, it may approach that source andinitiate two way communications with the source so that the source anddevice side control electronics can exchange configuration information.In an exemplary embodiment, when sufficient information has beenexchanged by the source and the device, and when the vehicle resonatorhas been positioned substantially in the near vicinity of the sourceresonator, the source and vehicle sides may switch to their Dockingstates.

In an exemplary Docking state, both source and device may confirm theircompatibility and an alignment error signal may be provided to thevehicle driver so that he/she can maneuver the car into proper position.Once in position, the drive train of the vehicle may be disabled and thesource and device may enter the Coupled state.

In an exemplary embodiment, a ‘Charge Request’ may be sent from thevehicle—either automatically or driver initiated, and may be received bythe source. In the Coupled state, there may be further exchange ofconfiguration information, safety checks, and the like. Once those arepassed, both sides may enter the Ready to Charge state.

In an exemplary embodiment, in the Ready to Charge state, the vehiclemay issue a ‘Start Charging’ command and both the source and the vehiclemay enter the Charging state as the source power ramps up. In theCharging state, both source and vehicle may perform monitoring andlogging of data, faults, and other diagnostics. Logging and monitoringmay include, but may not be limited to an event loop that looks forhazardous and/or restricted Foreign Object Debris (FOD), overloads,unexpected temperature and/or efficiency excursions, and otherasynchronous events.

In exemplary and non-limiting embodiments, hazard and/or restrictedobject detection that occurs in the source during any of the poweredstates may cause the source to switch into its Anomaly state. Ifwireless communication is still working, the vehicle may be notified andmay also drop into its Anomaly state. If wireless communication is down,the vehicle may enter its Anomaly state because it didn't ask for thewireless power to be shut down and because the wireless communicationswatchdog timer expires.

In an exemplary embodiment, where the vehicle has entered the Anomalystate, state, the vehicle may send a message to the source that resultsin the source entering its Anomaly state.

In an exemplary embodiment, where the source has entered the Anomalystate, the source may send a message to the vehicle that results in thevehicle entering its Anomaly state.

In an exemplary embodiment, the source and/or vehicle may automaticallybegin a process for handling or disposition of the anomaly. The processmay involve the source and vehicle exchanging health and statusinformation to help discover the cause of the anomaly. Once the cause isdetermined, the source and vehicle may select a pre-planned action thatcorresponds to the cause. For example, in the event that detection offoreign object debris caused the anomaly, the source may reduce thepower transfer level to a safe level where the foreign object debrisdoes not overheat. In another example, in the event that the loss of RFcommunication was the cause, the source may stop power transfer until RFcommunication is re-established. In exemplary and non-limitingembodiments, where one or both sides of the system may have entered theanomaly state, the system may automatically communicate to a user thatthe system is in its Anomaly state. Communication may occur over theinternet, over a wireless network, or over another communications link.

In an exemplary embodiment, under normal operating conditions, chargingmay end when the vehicle sends a stop-charging (DONE) command to thesource. The source may immediately de-energize.

In this exemplary embodiment, after de-energizing, the source may returnto the coupled state and may notify the vehicle of its state change. Thevehicle may switch to the Coupled state and may receive additionalinformation about the charge engagement from the source. At this point,the vehicle may either stay put or it may depart. Once the source sensesthat a vehicle has departed, it may return to the Available state.

Not explicitly shown the figures are exemplary control loops that mayperform system safety and hazard monitoring, as well as localized FODdetection, for example. There a many ways a FOD detector might be usedincluding; prior to a source declaring itself Available, it may runthrough a series of diagnostic tests including FOD detection, in theDocking and in the Coupled states, the FOD detector could check forpotentially hazardous debris falling off of a vehicle and onto a sourceresonator, and before entering the Ready to Charge state, a FOD detectorreading may be part of a final safety check. In exemplary andnon-limiting embodiments, monitoring for FOD may occur during theCharging state. In exemplary and non-limiting embodiments, one, some orany anomalies or failed safety checks may turn down or shut down theamplifier and put both sides (source and vehicle) into their Anomalystates, where additional diagnostics can be safely performed.

FIG. 5 shows another representation of some potential steps if asequence of interactions in an exemplary embodiment of an EV wirelesspower transfer system. The diagram shows exemplary steps from thecharging sequence described above following Unified Modeling Language(UML) conventions:

-   -   Time flows in the downward direction    -   The vertical bars under each side represent activation of        different states    -   Arrows with solid lines indicate requests    -   Arrows with dashed lines indicate responses    -   Full arrow heads represent synchronous messages    -   Half arrow heads represent asynchronous messages    -   Arrows entering the diagram from off the page represent user        actions        Note that the diagram is not intended to show every message in        the exemplary engagement just some examples helpful to        understanding the interaction.

In exemplary embodiments of electric vehicle wireless power systems, avariety of control loops may be implemented to govern the operation ofthe wireless charging and/or powering of the electric vehicle. Someexemplary control loops for the exemplary system shown in FIG. 2 aredescribed below. The control loops described below may be sufficient forsome systems or they may need to be modified or added to ensure properoperation of other systems. The description of control loops should notbe interpreted as complete, but rather illustrative, to describe some ofthe issues considered when deciding whether system control loops mightbe fast, medium or slow in their response time, and whether or not theyshould be user reconfigurable.

Referring to FIG. 6, in an exemplary EV wireless power transfer system,a power factor corrector 601 may convert an AC line voltage 602 to a DCvoltage 603 for the source. It may provide active power factorcorrection to the line side and may provide a fixed or variable DCvoltage to the source amplifier. Control of a power factor corrector 601may be performed through a combination of hardware circuits and firmwarein the amplifier controller 604. For example hardware circuits may beused to control against transient or short-duration anomalies, e.g.exceeding hard set-point limits such as local currents or voltagesexceeding safety limits for circuit components, such as power MOSFETs,IGBTs, BJTs, diodes, capacitors, inductors, and resistors, and firmwarein the amplifier controller 604 may be used to control against longerduration and slower developing anomalies, e.g. temperature warninglimits, loss of synchronization of switching circuitry with the linevoltage, and other system parameters that may affect power factorcontroller operation.

Referring to FIG. 7, in an exemplary embodiment, an amplifier 701 mayprovide the oscillating electrical drive to the wireless power systemsource resonator coil 702. Hardware circuits may provide high-speedfault monitoring and processing. For example, violations of current andvoltage set points and amplifier half-bridge (H-bridge) shoot-throughmay need to be detected within less than one millisecond in order toprevent catastrophic failures of the source electronics.

On a medium timescale, the amplifier controller 703 (and 604 in FIG. 6)may monitor the impedance of the source coil 702 and may react toout-of-range impedance conditions in less than 500 ms. For example, ifthe impedance is too inductive and out-of-range, the efficiency of powertransfer may be reduced and the system may turn down or shut down toprevent components from heating up and/or to prevent inefficient energytransfer. If the impedance is inductive, but low and out of range, thesystem may react as when the resonator is too inductive, or it may reactdifferently, or more quickly, since transitioning from an inductive loadto a capacitive load may damage the source electronics. In embodiments,a hardware circuit may be used to sense if the load the amplifier isdriving has become capacitive and may over-ride other slowed controlloops and turn down or shut down the source to prevent the unit frombecoming damaged.

In embodiments, system-level power requirements may be determined on thevehicle side and may be fed back from the ADP (not shown) to the ASP704. Over I2C, the ASP 704 may request that the amplifier controller 703increment or decrement the power from the amplifier 701 for example. Thebandwidth of the power control loop may be limited by the latency in thewireless link and by the latency in communication between the ADP andthe battery manager.

Referring to FIG. 8, in some embodiments, a rectifier 801 may convertthe AC power received from the device resonator coil 802 to DC outputpower 803 for the vehicle, vehicle battery or battery charger. Amonitoring circuit for the rectifier output power, current and orvoltage, as well as for the battery charge state may provide thefeedback for closed-loop control of the system's power transfer. Therectifier 801, controlled by a rectifier controller 804, may control theoutput voltage to maintain it within the range desired by the batterymanagement system. Additional fault monitoring and an interface tovehicle charging control processes may be provided by the ADP 805.

In an exemplary embodiment, a rectifier module 801 may comprise afull-bridge diode rectifier, a solid-state switch (e.g. double pole,single throw (DPST) switch), and a clamp circuit for over-voltageprotection. Under normal operation, the full-bridge rectifier may sendDC power through the closed switch and the inactive clamp circuit to thebattery system. If the battery system needs more current, it may requestit from the ADP which may forward the request to the ASP on the sourceside. If the battery needs less current, the corresponding request maybe made. The speed with which these conditions must be detected,communicated, and acted upon may be determined by how long the systemcan safely operate in a non-ideal mode. For example, it may be fine forthe system to operate in a mode where the wireless power system isproviding too little power to the vehicle battery, but it may bepotentially hazardous to supply too much power. The excess powersupplied by the wireless source may heat components in the resonator,clamp circuit and/or battery charge circuit. The speed of the feedbackcontrol loop may need to be fast enough to prevent damage to thesecomponents but may not need to be faster than that if a faster controlloop is more expensive, more complex, and/or less desirable for anyreason.

In exemplary and non-limiting embodiments, a switch and a clamp mayprovide vehicle-side protection against potential failure modes. Forexample, if the vehicle side enters its Anomaly state, it may notify thesource which may subsequently enter its Anomaly state and may turn downor shut down the source power. In case the wireless link is down or thesource is unresponsive, the switch in the rectifier may open to protectthe battery system.

In an exemplary embodiment, an ADP could enter its Anomaly state inseveral ways. A few examples include:

-   -   The battery manager requests an emergency disconnect    -   The voltage clamp circuit is active for more than 3 seconds (or        some set period of time, potentially user settable and        reconfigurable)    -   The wireless communications link is down    -   The ADP does not update the watchdog timer in the rectifier        controller    -   A temperature, voltage, current, or other error-condition set        point is violated.

In an exemplary and non-limiting embodiment of a charging engagement,control-system information may flow across the following interfaces:

-   -   ASP-ADP: Wireless interface between the Application Source        Processor on the source side and the Application Device        Processor on the vehicle side.    -   ASP-Laptop: Wireless interface used to send a webpage with        source diagnostic information that can be displayed on a laptop        for demonstration, system configuration, and debug purposes.    -   ADP-Laptop: Wireless interface used to serve a webpage with        device diagnostic information that can be displayed on a laptop        for demonstration and debug purposes.    -   ASP-AmpCon: an I2C interface between the ASP and the amplifier        controller.    -   ADP-RectCon: an I2C interface between the ADP and the rectifier        controller.

In exemplary and non-limiting embodiments, the first interface (ASP-ADP)may be used to exchange the messages needed to support the exemplarySequence Diagram shown in FIG. 5. It may be that standardizationactivities will specify certain wireless communications protocols, suchas the IEEE 802.11p protocol and/or Dedicated Short Range Communications(DSRC) using a licensed band at 5.9 GHz. In exemplary and non-limitingembodiments that comply with standards, it may be that only certainwireless communications protocols will be supported by and used toimplement the wireless power system controls. In exemplary andnon-limiting embodiments not governed by standards, both known andproprietary wireless communications protocols may be supported by andused to implement wireless power system controls. In an exemplaryembodiment, a reconfigurable EV wireless power transfer system has beendemonstrated using the IEEE 802.11b unlicensed band (Wi-Fi) to implementthe system control commands and communication.

In exemplary and non-limiting embodiments, the second and thirddiagnostic interfaces may be for running demonstration purposes and toprovide diagnostic information in an easily accessible format. Theconnections with the laptop may also use 802.11b. A Wi-Fi enabled routermay be required for simultaneous support of wireless connections for theASP-ADP, ASP-Laptop, and ADP-Laptop. For demonstrations that onlyrequire the ASP-ADP connection, an 802.11b peer-to-peer connection couldbe used.

In exemplary and non-limiting embodiments, the fourth and fifthinterfaces may be between the ASPs, other system controllers, and dataloggers. Other system controllers may be implemented in physicallydistinct microcontrollers as described in the exemplary embodiment, orthey may be co-located in the same ASPs.

Some example interactions amongst the ASP, ADP, controllers and FODdetectors are described below. These are just some of the exampleinteractions, but in no way are the interactions contemplated by thisinvention limited to only the examples given below.

In an exemplary embodiment, an Application Source Processor (ASP) may bea microprocessor that holds the state information for the source side ofthe reconfigurable EV wireless power transfer system. Physically, it maybe implemented in a PIC-32 microcontroller. The software running on theASP may execute the state transitions described previously, as well asthe wireless communication with the vehicle side and potentially withthe diagnostic laptop (if present). It is anticipated that users maymodify or replace the software on the ASP and still operate thereconfigurable EV wireless power transfer system. FIG. 9 shows exemplaryinterfaces to and from an application source processor and FIG. 13 showsexemplary ASP control parameters. Referring to FIG. 9, Functionalinterfaces to the Application Source Processor 901 may include, but maynot be limited to:

-   -   Wi-Fi link 902 for communicating with the vehicle's ADP and for        a diagnostic display for user demonstrations, diagnostics and/or        customization (iPAD or laptop)    -   Serial Peripheral Interface (SPI) 903 serial-link over Ethernet        904 on a 2.4 GHz RF link for communicating with the vehicle's        ADP    -   Hardware support for Universal Asynchronous Receiver/Transmitter        (UART) 905 serial-link over Ethernet 904 on a 2.4 GHz RF link        for an alternative method of communicating with the vehicle's        ADP    -   Interface 915 to amplifier controller 906    -   I²C 907 for commanding and receiving status information    -   Interrupt 908 for high-priority tasks (e.g. FOD detection,        source or vehicle anomaly)    -   Bi-directional watchdog/heartbeat signal 909    -   FOD detection interface 910    -   Metal object detector 911    -   Temperature sensors 912    -   Living being sensor, such as capacitive sensors 913    -   System process interlock 914 inputs-used for higher-level        controllers that may need to shut down the source suddenly.    -   I²C interface to source side PIM (PCB Information Memory with a        unique identifier (UID), configuration settings, etc.)

In an exemplary embodiment, an ASP 901 may have a WirelessCommunications Link Interface. For example, the source-side ASP 901 maycommunicate with the vehicle-side ADP over a wireless communication link902. The wireless protocol may be implemented using TCP/IP over a 2.4GHz Wi-Fi link. The RF module may be IEEE Std. 802.11b compatible with a4-wire SPI interface to the ASP.

In an alternate embodiment, a communication interface using the ASP 901serial UART port 905 may be available as an option. The serial portmight interface to an external wireless module to support the link. Astandard UART interface 905 may provide the flexibility to use anyparticular wireless protocol 917 that a user may want.

In an exemplary embodiment, there may be an interface 915 between theASP 901 and the amplifier controller 906. An amplifier controller 906may provide low-level control of the source electronics, while the ASP901 may provide high-level control and may be responsible for theexecution of the overall system charging cycle. The interface 915 to theamplifier controller 906 may be presented as a set of control and statusregisters which may be accessible through an I²C serial bus 907. Such anarrangement could support user customization of the control algorithms.

In an exemplary embodiment, there may be an interface 910 between an ASP901 and a FOD detection subsystem. The ASP 901 may be able to receivepreprocessed digital data from a FOD processor 916. A FOD processor 916may be designed to perform signal conditioning and threshold detectionfor the various types of sensors (e.g., 911, 912, 913) connected to it.Upon detection of FOD, the FOD processor 916 may interrupt the ASP 901and transmit the FOD decision-circuit results. The ASP 901 may then takeappropriate action (e.g. shut down the power, go to a low-power state,issue a warning, etc.) The FOD processor 916 may also transmit thepre-decision signal-conditioned data in digital form to the ASP 901 sothat soft decision algorithms that use other information can beimplemented in the ASP 901.

In an exemplary embodiment, there may be an interface between an ASP 901and a System Interlock 914 subsystem. An interlock interface may consistof a set of optically coupled digital inputs which may act as systemenables. The interlocks 914 may be externally generated signals whichmay be asserted to turn on the system. The interlocks 914 may also beable to be used by the user to shut down the system on command. Thesystems and signals that feed the external interlock signals (shutdownswitch, additional FOD detection, infrastructure fault detection, etc.)may be application specific.

In an exemplary embodiment, there may be an interface between an ASP 901and a Positioning and Alignment Interface. A positioning and alignmentinterface may communicate data from a vehicle alignment and positioningsensor to an ASP 901 to determine whether sufficient wireless powertransfer efficiency may be achieved given the measured relative positionof source and device resonators. If the resonators are not sufficientlywell aligned, the ASP 901 may communicate to the device ADP and instructthe system to generate a message to the driver that the vehicle needs tobe repositioned and to inhibit system turn-on until proper positioningis established.

In embodiments, there may be an interface between an ASP 901 and aDiagnostic/Debug subsystem. For the purposes of demonstrations,customization, and testing, a diagnostic/debug interface may beavailable across a wireless link between an ASP 901 and a laptop, ortablet, or smartphone or any other processing unit that preferablycomprises a display. In some embodiments, the wireless communicationsconnection may be through a dedicated Wi-Fi network. In embodiments, theinterface may allow a laptop, or other external controller, to put theEV wireless power transmission system in a diagnostic and/orcustomization mode where preset interlocks may be over-ridden and statechanges may be forced onto the ASP.

In embodiments, this interface may also allow a laptop, or otherexternal controller, with a Wi-Fi capability to access the ASP 901. Forexample, the ASP 901 may be capable of streaming state information tothe laptop which may store it in a log file. Parameters that can bestored in the log file may include:

-   -   Time-stamped events such as state changes, messages passed,        messages received    -   Measured voltages, currents, temperatures, and impedances that        are being compared to set points by the ASP or amplifier        controller.    -   Configuration information such as software/firmware versions,        hardware IDs, etc.    -   The log file should be able to be viewed on the laptop and        incorporated into a spreadsheet for later analysis.

FIG. 10 shows exemplary interfaces to and from an application deviceprocessor and FIG. 14 shows exemplary ADP control parameters. Referringto FIG. 10, in embodiments, an Application Device Processor (ADP) 1001may be a microprocessor that holds the state information for the vehicleside of an EV wireless power transfer system. Physically, it may beimplemented in a PIC-32 microcontroller. In embodiments, the softwarerunning on the ADP 1001 may execute the state transitions describedpreviously, as well as the wireless communication with the source sideand the diagnostic laptop, or other external controller. Users maymodify or replace the software on the ADP 1001 to customize theoperation and control of an EV wireless power transfer system.

In embodiments, functional interfaces to the Application DeviceProcessor 1001 may include but may not be limited to:

-   -   Controller Area Network (CAN) Bus 1002 implemented on the        physical layer (PHY) on the device side for use with vehicle        communication, diagnostic equipment, and/or measurement and or        monitoring equipment    -   Serial-link over Ethernet 1003 on a 2.4 GHz RF link for        communicating with the Source ASP    -   Wi-Fi 1004 to a diagnostic display for user demonstrations        and/or customizations (iPAD or laptop)    -   Interface to a rectifier controller 1005    -   I²C 1006 for commanding and receiving status information    -   Interrupt 1007 for high-priority tasks (e.g. FOD detection,        vehicle anomaly)    -   Bi-directional watchdog/heartbeat signal 1008    -   System process interlock 1009 inputs used for higher-level        controllers on a vehicle that may need to disable the charging        cycle.    -   I²C interface to Device side PIM (PCB Information Memory with        UID, configuration settings, etc.)

In some embodiments, there may be an interface 1011 between an ADP 1001and a CAN Bus 1002. In some embodiments, the ADP 1001 may include a CANbus interface 1011. In embodiments, software running on an ADP 1001 maybe augmented by a user to support a CAN bus interface 1011 even if theas-designed and/or as-delivered EV wireless power transfer system didnot include this functionality.

In embodiments, a vehicle-side Application Device Processor 1001 mayhave a Wireless Communications Link Interface. For example, adevice-side ADP 1001 may communicate with the source-side ASP over awireless communication link.

The wireless protocol may be implemented using TCP/IP over a 2.4 GHzWi-Fi link 1004. The RF module may be IEEE Std. 802.11b compatible witha 4-wire SPI interface 1010 to the ADP.

In embodiments, there may be an interface 1005 between an ADP 1001 and arectifier controller 1012. The ADP 1001 may communicate with therectifier controller 1012 over an interface 1005 that may be similar tothe one between the ASP and the amplifier controller. A rectifiercontroller 1012 may provide low-level control of the device electronics,while the ADP 1001 may provide high-level control and may be responsiblefor the execution of the overall system charging cycle. The interface1005 to the rectifier controller 1012 may be presented as a set ofcontrol and status registers which may be accessible through an I²Cserial bus 1006. Such an arrangement could support user customization ofthe control algorithms. The interface 1005 may also consist of, anInterrupt Request input 1007 and a set of uni-directionalwatchdog/heartbeat outputs 1008.

In an exemplary embodiment, there may be an interface between an ADP1001 and a Positioning and Alignment Interface. A positioning andalignment interface may communicate data from a vehicle alignment andpositioning sensor to an ADP to determine whether sufficient wirelesspower transfer efficiency may be achieved given the measured relativeposition of source and device resonators. If the resonators are notsufficiently well aligned, the ADP may communicate to the source ASP andinstruct the system to generate a message to the driver that the vehicleneeds to be repositioned and to inhibit system turn-on until properpositioning is established.

In embodiments, there may be an interface between an ADP 1001 and aSystem Interlock subsystem 1009. This interface may be analogous to thatdescribed between an ASP and a System Interlock subsystem. It could beused by the battery manager to force a shutdown of the EV wireless powertransfer system. For example, if the interlock 1009 is de-asserted, theADP 1001 may enter its Anomaly state and may demand that the source shutdown immediately and may open the switch in the rectifier circuit. Inthe case of an unresponsive source or an interrupted wirelesscommunications link, the ADP 1001 may open the switch within 3 seconds,or an appropriate period of time, and communicating a command that thesource shut down.

In embodiments, there may be an interface between an ADP 1001 and aDiagnostic/Debug subsystem. For the purposes of demonstrations,customization, and testing, a diagnostic/debug interface may beavailable across a wireless link between an ADP and a laptop, or tablet,or smartphone or any other processing unit that preferably comprises adisplay. In some embodiments, the wireless communications connection maybe through a dedicated Wi-Fi network. In embodiments, the interface mayallow a laptop, or other external controller, to put the EV wirelesspower transmission system in a diagnostic and/or customization modewhere preset interlocks may be over-ridden and state changes may beforced onto the ADP.

In embodiments, this interface may also allow a laptop, or otherexternal controller, with a Wi-Fi capability to access the ADP. Forexample, the ADP may be capable of streaming state information to thelaptop which may store it in a log file. Parameters that can be storedin the log file may include:

-   -   Time-stamped events such as state changes, messages passed,        messages received    -   Measured voltages, currents, temperatures, and impedances that        are being compared to set points by the ADP or rectifier        controller.    -   Configuration information such as software/firmware versions,        hardware IDs, etc.    -   The log file could be viewed on the laptop and dumped into excel        for later analysis.

FIG. 11 shows exemplary interfaces to and from an amplifier controllerand FIG. 15 shows exemplary amplifier control parameters. Referring toFIG. 11, in embodiments of EV wireless power transfer systems, anamplifier controller 1101 may provide low-level control to a PowerFactor Corrector (PFC) 1102 and a switching amplifier 1103. Theinterfaces between an amplifier controller 1101 and other systemcomponents may include, but may not be limited to:

-   -   Interface 1104 to Application Source Processor 1105        -   I²C 1106        -   Interrupt 1107        -   Bi-directional Heartbeat/Watchdog 1108    -   PFC Hardware control interface 1109    -   Amplifier hardware control interface 1110    -   System critical interlock inputs 1111    -   System On/Off

FIG. 12 shows exemplary interfaces to and from a rectifier controllerand FIG. 16 shows exemplary rectifier control parameters. Referring toFIG. 12, in embodiments of EV wireless power transfer systems, arectifier controller 1201 may provide high speed monitoring of rectifierpower and system critical fault control. The interfaces between arectifier controller 1201 and other system components may include, butmay not be limited to:

-   -   I²C interface 1202 to Application Device Processor 1203        -   I2C 1204        -   Interrupt 1205        -   Bi-directional Heartbeat/Watchdog 1206    -   Rectifier hardware control/status interface 1207    -   Fault indicators such as over current, over voltage, over        temperature, clamp circuit activated, etc.    -   Device side system critical interlock inputs 1208.

An A reconfigurable EV wireless power transmission system may bepartitioned into notional subsystems so that the interactions betweensubsystems may be studied and design decisions made be made as to whichcontrol functions and set-points may be customizable by a user whilestill ensuring safe, efficient and reliable performance of the system.One method to analyze the system performance impact of allowingcustomization and/or reconfigurability of the control architectureand/or algorithms and/or set-points is to perform a Failure Mode EffectsAnalysis (FMEA). A preliminary FMEA may comprise a prioritized listingof the known potential failure modes. FMEA may need to be an on-goingactivity as new system failure modes are identified.

In exemplary and non-limiting embodiments, an FMEA process that scorespotential failure modes in a number of categories may be used toidentify the severity of certain failure scenarios. Categories that maybe used to identify customizable parameters may include, but may not belimited to

-   -   Severity (1-10): If the failure mode occurs, how severe (SEV) is        the impact to system functionality, performance, or safety? A        score of 10 indicates a major hazard and a score of 1 indicates        a minor loss of performance or functionality.    -   Likelihood (1-10): How likely is the failure to occur? A 10        indicates almost certain occurrence while a 1 indicates a very        remote chance of occurrence (OCC).    -   Undetectability (1-10): How likely is it that the failure will        be detected (DET) and reacted to by the system during operation?        A 10 indicates that the control architecture is very unlikely to        detect the failure while a 1 indicates almost certain detection.

In exemplary and non-limiting embodiments, the potential failure modesmay be prioritized according to their Risk Priority Number (RPN)-whichis merely the product of their three category scores.

While the invention has been described in connection with certainpreferred exemplary and non-limiting embodiments, other exemplary andnon-limiting embodiments will be understood by one of ordinary skill inthe art and are intended to fall within the scope of this disclosure,which is to be interpreted in the broadest sense allowable by law. Forexample, designs, methods, configurations of components, etc. related totransmitting wireless power have been described above along with variousspecific applications and examples thereof. Those skilled in the artwill appreciate where the designs, components, configurations orcomponents described herein can be used in combination, orinterchangeably, and that the above description does not limit suchinterchangeability or combination of components to only that which isdescribed herein.

All documents referenced herein are hereby incorporated by reference.

What is claimed is:
 1. A method of operating a wireless energy transfersystem executed by a control processor of the wireless energy transfersystem, the method comprising: identifying a priority rank for each of aplurality of system faults, each priority rank representing an executionpriority for a corresponding one of the system faults; monitoring thesystem for activation of faults, wherein the monitoring comprises:repeatedly executing a first control loop associated with a first faulthaving a first priority rank indicative of a high priority fault, thefirst control loop having an associated first execution time period T₁;and repeatedly executing a second control loop associated with a secondfault having a second priority rank indicative of a moderate priorityfault, the second control loop having an associated second executiontime period T₂; and transmitting a signal to a power source controllerin response to detecting that one of the first and second faults isactive, wherein T₂ is larger than T₁ so that during a monitoring timeperiod, the first control loop is executed more frequently than thesecond control loop; and wherein the signal is transmitted at a speedcorresponding to the priority rank of the active fault.
 2. The method ofclaim 1, comprising transmitting the signal to the power sourcecontroller during or following execution of at least one of the firstand second control loops.
 3. The method of claim 1, wherein the signalcomprises an interrupt signal that causes the power source controller toreduce power supplied to a resonator coil of the wireless energytransfer system.
 4. The method of claim 1, further comprising:transmitting the signal at a third speed if the first fault is active;and transmitting the signal at a fourth speed if the second fault isactive, wherein the fourth speed is less than the third speed.
 5. Themethod of claim 1, wherein identifying the priority rank for each of theplurality of system faults comprises determining a risk priority number(RPN) for each of the system faults.
 6. The method of claim 1, whereinthe power source controller is an amplifier controller.
 7. The method ofclaim 1, wherein the power source controller is a rectifier controller.8. The method of claim 1, wherein the respective priority ranks are eachbased on a combination of a fault severity, a fault likelihood, and afault detectability.
 9. The method of claim 1, further comprisingproviding a periodic signal to the power source controller.
 10. Themethod of claim 1, wherein one of the plurality of system faults is adetection signal from a foreign-object-debris (FOD) detector.
 11. Themethod of claim 1, wherein one of the plurality of system faults is asource anomaly.
 12. The method of claim 1, wherein one of the pluralityof system faults is a vehicle anomaly.
 13. The method of claim 1,wherein one of the plurality of system faults is an out-of-rangeimpedance.
 14. The method of claim 1, wherein the first fault comprisesa member selected from the group consisting of an over-current fault, anover-voltage fault, an over-temperature fault, a transistorshoot-through current fault in an amplifier, a ground-fault circuitinterrupt, and an open system interlock.
 15. The method of claim 1,wherein the second fault comprises a member selected from the groupconsisting of a temperature set-point violation, an out-of-rangeimpedance for a source resonator, a foreign-object-debris (FOD)detection signal, and a minimum efficiency set-point violation.
 16. Themethod of claim 1, further comprising repeatedly executing a thirdcontrol loop associated with a third fault having a third priority rankindicative of a low priority fault, the third control loop having anassociated third execution time period T₃, wherein T₃ is larger than T₂.17. The method of claim 16, wherein the third fault comprises a memberselected from the group consisting of a system stop message, aradio-frequency communication signal, an authentication signal, acharging request, and a configuration signal.
 18. A method of operatinga wireless energy transfer system, comprising: executing first andsecond groups of control loops on a control processor, wherein the firstgroup of control loops comprises one or more members each associatedwith a different one of a first group of system faults, and wherein thesecond group of control loops comprises one or more members eachassociated with a different one of a second group of system faults;determining whether any members of the first and second groups of systemfaults are active based on the execution of the first and second groupsof control loops; transmitting a control signal to a power sourcecontroller when any one or more members of the first and second groupsof system faults are active; and adjusting power supplied to a resonatorof the system by the power source controller in response to the controlsignal, wherein each member of the first group of control loops isexecuted at a speed that is faster than a speed at which each member ofthe second group of control loops is executed; and wherein the controlsignal is transmitted at a first speed if a member of the first group ofsystem faults is active, and at a second speed slower than the firstspeed if a member of the second group of system faults is active. 19.The method of claim 18, further comprising: executing a third group ofcontrol loops on the control processor, wherein the third group ofcontrol loops comprises one or more members each associated with adifferent one of a third group of system faults; determining whether anymembers of the third group of system faults are active based on theexecution of the third group of control loops; and transmitting thecontrol signal to the power source controller when any members of thethird group of system faults are active, wherein each member of thethird group of control loops is executed at a speed that is slower thana speed at which each member of the second group of control loops isexecuted; and wherein the control signal is transmitted at a third speedslower than the second speed if a member of the third group of systemfaults is active.
 20. The method of claim 18, further comprisingassociating a priority rank with the control loops of the first andsecond groups, and executing the control loops of the first and secondgroups according to the priority ranks.
 21. The method of claim 18,wherein the first group of system faults comprises an over-currentfault, an over-voltage fault, an over-temperature fault, a transistorshoot-through current fault in an amplifier, a ground-fault circuitinterrupt, and an open system interlock.
 22. The method of claim 18,wherein the second group of system faults comprises a temperatureset-point violation, an out-of-range impedance for a source resonator, aforeign object debris (FOD) detection signal, and a minimum efficiencyset-point violation.